math-modespacingsubscripts
is there a way to remove the space between the variable and the lowercase letter as standard in math environment?
by now i'm using this:
\begin{equation}
a\;b_{\! c}\;d
\end{equation}
Without \! the space looks to big. Now i thought, if it is possible to set this by default in the math environment.
Math binary operators and relations automatically add appropriate spaces between the symbol and their operands. If you want to remove this space, you can turn the operator into a regular symbol by enclosing it in braces. For example
$1024 {\times} 768$
If you will be using this often you can also define a new command and say something like
\newcommand{\stimes}{{\times}}
$1024 \stimes 768$
where \stimes is a symbol version of the \times operator.
TeX has a finely balanced system of setting spaces between various types of math "atoms". For example, consider the following simple formula:
$y = b + cx$
Observe that the distance between y and = (and also between = and b) is slightly larger than that between b and +, which again exceeds that between c and x. This is done on purpose, of course, and the choices involved have proven their desirability over decades.
If you were to systematically increase the spacing between any two "atoms" that are multiplied together (such as c and x in the example above), you should also be willing to increase the spacing between all other types of "atoms" in order to preserve the overall balance. To claim that this would be a rather tricky enterprise would be a rather strong understatement.
In short, it's best not only to get used to TeX's way of typesetting mathematics but also to appreciate it for the high standard it sets. TeX's method is the standard against which all other systems for typesetting mathematics are judged and against which they, regrettably, almost invariably fail.
Best Answer
Please remember that (La)TeX was designed carefully by people who know much, much more than we'll ever learn about typesetting. Changing such rather common constructions is ill-advised. Maybe in some specific case the default isn't ideal.